Electrical polymer insulators are used in power transmission and distribution systems to provide mechanical support for the conductors and provide electrical insulation between the high voltage conductors and grounded tower structures. A corona protection device is located at the line end and/or the ground end of the insulator and eliminates the corona discharge from the insulator. Elimination of the corona discharge protects the surface of the insulator from polymeric material deterioration caused by electric stress. Additionally, eliminating the corona discharge reduces television and/or radio noise created by the corona discharge.
A problem with existing corona protection devices is the number of parts required to assemble the corona protection device, thereby increasing the manufacturing costs. Additionally, more parts must be carried to a job site by an installer, which decreases the speed and efficiency with which the corona protection devices may be installed. Since existing corona protection devices require various parts to completely assemble the device, if one part is lost or missing the device cannot be properly assembled and an installer must make a return trip to finish installation of the corona discharge device. A need then exists for a collar assembly having few parts, thereby reducing manufacturing costs and providing quick installation.
Other problems with existing corona protection devices involve poor seals being formed between the corona protection device and the insulator, as well as the corona protection device being poorly secured to the insulator. Poor seals with and connections to the insulators result in a highly ineffective corona protection device, and often results in the corona protection device failing. Thus, a need exists for a collar assembly having a good seal and connection to the insulator.
Examples of conventional corona protection devices include U.S. Pat. No. 2,867,682 to Smith et al.; U.S. Pat. No. 3,239,600 to Bethea, Jr.; U.S. Pat. No. 4,198,538 to Lusk; U.S. Pat. No. 5,488,199 to Selsing et al.; U.S. Pat. No. 6,265,669 to Richards; U.S. Pat. No. 6,388,197 to Zhao et al.; the subject matter of each of which is hereby incorporated by reference.
A need exists for an improved insulator collar assembly.